Four TADs supported Herbst mechanics: A case report

Skeletal and dental effects of Herbst appliance anchored with temporary anchorage devices: A systematic review with meta-analysis

BACKGROUND

The aim was to evaluate the efficiency of using temporary anchorage devices (TADs) in minimizing the anchorage loss and increasing the skeletal effects during correction of Class II malocclusion with Herbst appliance.

MATERIALS AND METHODS

Search without restrictions was performed up to January 2021 in three electronic databases (CENTRAL, MEDLINE and EMBASE) for randomized controlled trials (RCTs), prospective and retrospective cohort studies. The included studies assessed the dental and skeletal changes in Class II malocclusion patients who were treated using Herbst appliance with or without TADs. The strength of evidence was ranked using GRADE.

RESULTS

Fifty-five records were initially retrieved. A total of 6 studies with 198 patients were finally considered. 4 studies were included in the meta-analysis. The meta-analysis showed that using TADs with acrylic splint Herbst appliance was effective in controlling the inclination of mandibular incisors by a mean difference of -5.49 degrees (95% C.I [-7.36, -3.63], P < .001) when compared to Herbst appliance alone. The results showed also that incorporating TADs with Herbst treatment resulted in greater mandibular skeletal effects including increasing mandibular bone base length by mean difference of 2.22 mm (95% C.I [0.82. 3.61], P = .002) and mandibular length by mean difference of 3.7 mm (95% C.I [1.55, 5.85], P < .001) when compared to Herbst appliance alone.

CONCLUSIONS

Based on a very low level of confidence, it seems that incorporating TADs during orthodontic treatment with Herbst appliance results in minimizing the anchorage loss and increasing the skeletal effects of Herbst appliance during correction of Class II malocclusion.

Influence of Vertical Facial Growth Pattern on Herbst Appliance Effects in Prepubertal Patients: A Retrospective Controlled Study

Introduction

The Herbst device is widely used for correction of class II malocclusions; however, most of the researches carried out on the Herbst appliance in literature do not take into account patients with a different mandibular divergence. The aim of this study was to investigate the effects of Herbst on dental and skeletal structures and to evaluate possible influence of vertical facial growth patterns.

Methods

A retrospective study was conducted on lateral cephalograms of 75 growing patients (mean age: 9.9 ± 1.9 years) with class II malocclusion treated with Herbst. Subjects were divided into 3 groups using the mandibular divergence index (SN and GoMe angle). Cephalometric parameters were evaluated using the modified SO (sagittal occlusion) Pancherz's analysis. A statistical analysis was conducted to evaluate differences among groups using ANOVA.

Results

Our study showed differences in response to treatment depending on patient's facial vertical growth pattern. Cranial base angle and mandibular rotation were significantly different (p < 0.05) between hypodivergent patients and normodivergent patients and between hypodivergent and hyperdivergent subjects.

Conclusion

Hypodivergent patients increased their mandibular divergence during treatment to a greater extent than normodivergents; moreover, hyperdivergent patients exhibited a decreased mandibular divergence at the end of the treatment.